Advanced driver assistance systems (ADAS) automate, enhance or otherwise adapt other systems of the ADAS equipped vehicle. For example, some ADAS features are designed to avoid collisions and other accidents by alerting the driver to the potential for a collision or accident occurring, by taking over driving action when such potential for a collision or accident is determined, or by implementing other safeguards. Other ADAS features include systems that automate lighting, provide adaptive cruise control, automate braking, incorporate GPS/traffic warnings, connect to smart phones or other devices, alert the driver to dangers, keep the driver in the correct lane, or make the driver aware of objects present in blind spots.
Highly Automated Driving (HAD) systems are ADAS systems that automate vehicle driving on highways and the like. HAD systems generally require that the driver take over driving responsibility, and thus initiate manual driving, under certain circumstances. However, HAD systems are able to maintain autonomous driving under most circumstances likely to be encountered on highways and the like. HAD systems are classified as Level 3 automated driving systems by the National Highway Traffic Safety Administration.
Fully Automated Driving (FAD) systems are ADAS systems that fully automate vehicle driving. The driver is not required to monitor traffic, or otherwise take over the driving responsibility, and can be occupied with another task. FAD systems are classified as Level 4 or 5 automated driving systems by the National Highway Traffic Safety Administration.
Each of these systems typically utilize cameras to capture images of the environment surrounding the vehicle, which images are then processed by the system to determine the environmental conditions relevant to that system. Each such camera typically includes a lens with a fixed focal length (i.e., the distance at which the lens is focused) that is appropriate for the environmental condition that is relevant to the particular ADAS/HAD/FAD system.
A problem with such a configuration is that a camera with a near-focus lens is typically only used for near-range imaging, e.g., lane detection, because objects located in the mid-range and far-range distances appear out-of-focus to the image sensor, and are therefore more difficult to resolve. Cameras respectively equipped with mid-focus or far-focus lenses are likewise typically only used in connection with those ranges. This results in reduced system performance.
A multi-camera solution has been proposed in which the ADAS/HAD/FAD system is provided with three cameras, each of which is equipped with a different one of near-focus, mid-focus and far-focus lenses. While the multi-camera solution provides better performance over the target range, it still only provides in-focus images in the three defined focus sweet spots. Moreover, such systems are more complex, have higher failure rates, consume more energy, are larger, and are more costly. Thus, there is a clear trade-off between each of these factors and system performance.